In recent years, with the advances of the genome project, genome nucleotide sequences of a variety of organisms have been found, which has increased interest in using probe arrays of biopolymer microchips. The probe array is extensively used to perform gene expression profiling and genotyping to detect mutation and polymorphism, such as single nucleotide polymorphism (SNP), to analyze proteins and peptides, to perform screening of potential drugs and to develop and fabricate new drugs.
Currently, a widely available probe array may be manufactured by, for example, exposing to light predetermined regions of a substrate which contain functional groups protected by a protective group, exposing the functional groups in the predetermined regions, and then performing in-situ synthesis of monomers.
Additionally, etching is of significance during semiconductor manufacture, and with the recent trend of high integration of semiconductor devices, a photolithography process is widely used in forming fine patterns of a semiconductor device.
In the photolithography process, a mask pattern, for example, a photoresist pattern, is formed, and a target mask to be etched is etched using the photoresist pattern as an etch mask. Here, in order to reduce light reflection of the target mask during exposure employed in the photolithography process, an anti-reflective coating may be employed.
In synthesizing probes of a probe array, in order to minimize damages of monomers, an i-line light source is generally used, and a non-ionic type photoacid generator is typically used as a photoacid generator for i-line light source. However, the non-ionic type photoacid generator generates a relatively weak acid. Thus, for the purpose of protecting a protective group that protects functional groups of the monomers, a light source of relatively high exposure energy should be used.